Gasoline vapors that are released during the dispensing of fuel into the tanks of automobiles and other vehicles, constitute an important source of air pollution. A vapor recovery system which has been recently adopted in at least one state of the United States, includes a fuel dispensing head with a bellows surrounding the fuel-dispensing nozzle. When filling a fuel tank, the operator inserts the protruding end of the nozzle into the tank, and presses the filler head with considerable force against the vehicle. The high force assures good sealing of the bellows end to the area around the fuel tank opening, to permit the effective withdrawal of vapors by a pump connected to the inside of the bellows. The dispenser head will not operate until the nozzle has been inserted a considerable depth of several inches into the tank.
In automobiles which include an extension tube extending down to the tank, the necessity for insertion of the nozzle several inches into the extension tube does not hamper substantially complete filling of the tank. In motorcycles, wherein there is normally no long extension tube leading to the tank, the necessity for deep insertion of the nozzle to operate the dispenser, can create problems. If the nozzle is inserted several inches into the tank, then when the tank is half full the fuel level will reach the shut off sensor on the nozzle and prevent any further filling of the tank. If the operator withdraws the nozzle so that only its tip lies in the tank, which is the technique presently used to completely fill a motocycle tank, then the vapor recovery bellows will not be compressed and the dispenser will not operate.
It is possible to provide special dispenser attachments to enable the complete filling of a motor cycle tank, but since most fuel is sold to automobile owners, it is likely that many gasoline stations will not carry such attachments. It is also possible to utilize a detachable filler extension tube which can be attached to the motorcycle tank during filling, and thereafter stored out of the way. However, where such storage of an extension tube is separate from the tank, the storage and retrieval is annoying and it is likely that the extension tube will be lost. Where the extension tube is to be stored within the tank, the need to operate a mechanism to withdraw and later store the tube can be annoying and the mechanism for achieving this can add complications. A filler device which enabled deep insertion of a nozzle into a tank, so as to operate a vapor recovery mechanism on the dispenser, but which enabled substantially complete filling of the tank, would be of considerable value, especially for use on motorcycle tanks.